The polymerization-type dye has high strength, good film-formability, solvent resistance and processability, and has excellent transference resistance and moisture resistance, which thus represents a new field within the macromolecule and dye chemistry. The polymerization-type dye of polycarboxylic acid has carboxyl group supported on the molecule, which can not only endue the dye water-solubility, so as to be useful for coloring the natural fiber and leather; but also change into hydrophobic dye owing to the ability of the carboxyl group to be removed or be amidated or esterified under certain conditions, so as to color the synthetic fiber. The polycarboxylic acid dye hereby is broadly applicable, and thus is much applicably valuable and has great prospect.
Lewis et al. produce a tetra-carboxylic acid dye by reacting an aspartic acid and a dye of C.I. reactive red 120 with di-active groups, which dye is baked at a temperature of 180-210° C. for 1-2.5 minutes, reacted with fiber via a transition state of acid anhydride for dyeing. However, the dye has low dye fixation, and the temperature for dyeing is relatively high (Lewis, AATCC, 1995, 536-544). U.S. Pat. Nos. 3,911,164 and 6,764,541 disclose to polymerize the maleic anhydride and methylvinyl ether to obtain a copolymerized polymer, which is then reacted with a dye, so as to obtain a carboxyl-comprising copolymerized macromolecule dye; whilst the incorporation of copolymerized group decreases the content of acid anhydride in the polymer, resulting in decreased amount of dye grafted thereto. Anyhow, the polycarboxylic acid dye is one with great prospect due to strong binding force and ease to syntheses; however, research on the polycarboxylic acid dye is currently insufficient. In particular, the polycarboxylic acid dye based on polymaleic acid having a macromolecule skeleton of polymaleic acid homopolymer, linked with organo-small molecule dye via a bridge group of amide or ester bond.
Therefore, the purpose of the present invention is to provide a new polycarboxylic acid dye with low polymerization degree, which dye has a macromolecule skeleton of polymaleic acid homopolymer, linked with organo-small molecule dye via a bridge group of amide or ester bond. The dye is useful for dyeing and printing leather, natural fiber and synthetic fiber; wherein the color fastness of dye is increased due to the presence of polycarboxyl group increasing the binding force between the dye and the colored substrate. The dye is synthesized by simple process, is convenient to use, and thus has broad application prospect.